JP4529540B2 - Air conditioning apparatus and compressor preheating method - Google Patents

Description

  The present invention relates to an air conditioner including an inverter device that heats a compressor at a low temperature, shortens a heating rise time, protects the compressor, and the like, and a compressor preheating method.

  A conventional vehicle air conditioner equipped with an electric compressor will be described as an example.

  FIG. 7 is a configuration diagram of a vehicle air conditioner equipped with a conventional electric compressor, and constitutes a heat pump cycle.

  In FIG. 7, 26 is an indoor fan, 27 is an air inlet, 12 is a fan duct, 13 is an indoor heat exchanger, 14 is an air outlet, 15 is a throttle device, 16 is an outdoor heat exchanger, and 17 is an outdoor fan. A fan, 18 is a four-way switching valve for switching between refrigerant flow and selecting cooling or heating, 19 is an electric compressor with a built-in electric motor and driven by the electric motor, 20 is an inverter device for operating the electric motor, and 1 is an inverter device 20 is a battery serving as a power source, 21 is an air conditioner controller that controls the indoor blower fan 26, the inverter device 20, the four-way switching valve 18, the outdoor blower fan 17, and the like, and 22 is an on / off switch for the indoor blower fan 26, and a strength setting. Indoor fan switch, 23 is an air conditioner switch for selecting cooling or heating or OFF, 24 is a temperature control switch, and 25 is a vehicle controller. Respectively show a communication device for communicating with over la.

  In the above configuration, for example, when the ventilation is turned on by the indoor blower fan switch 22 and weakened by the air conditioner switch 23, and the cooling is instructed by the air conditioner switch 23, the air conditioner controller 21 sets the four-way switching valve 18 to the solid line in the figure, The evaporator 13 is operated as an evaporator, the outdoor heat exchanger 16 is operated as a condenser, the outdoor fan 17 is turned on, and the indoor fan 26 is set weak.

  Further, by varying the rotational speed of the electric compressor 19 using the inverter device 20 according to the temperature adjustment switch 24, the capacity of the electric compressor 19 is adjusted and the temperature of the indoor heat exchanger 13 is adjusted.

  Further, when the cooling or heating is turned off by the air conditioner switch 23, the electric compressor 19 and the outdoor blower fan 17 are turned off.

  The electric compressor 19 used here and its drive circuit will be described.

  FIG. 8 is a partial cross-sectional view of a conventional electric compressor. As an example, the electric compressor includes a DC brushless motor.

  In FIG. 8, the electric compressor 19 is provided with a compression mechanism 28, an electric motor 31, and the like in a metal casing 32. The refrigerant is sucked from the suction port 33 and compressed by driving the compression mechanism portion 28 (scroll type in this example) by the electric motor 31. The compressed refrigerant passes through the vicinity of the electric motor 31 and is discharged to the discharge port 34. More discharged. A terminal 39 connected to the winding 4 of the electric motor 31 inside the metal casing 32 is connected to, for example, the inverter device 20 shown in FIG.

  FIG. 9 shows an electric circuit diagram for driving a conventional electric compressor.

  In FIG. 9, 1 is a battery, 2 is a switching element for inverter operation, 3 is a diode for inverter operation, and 40 is an inverter circuit section. Reference numeral 4 denotes a stator winding of the electric motor, and reference numeral 5 denotes a magnet rotor of the electric motor. 6 is a current sensor for detecting power supply current to calculate power consumption and protecting switching elements, 41 is a capacitor for smoothing current due to inverter operation, 49 is a charging resistor for charging the capacitor 41, 43 is charging for the capacitor 41 The relay is closed after completion and supplies power to the inverter circuit unit 40.

  10 is a voltage detector for detecting the voltage of the capacitor 41, 11 is a position detection circuit for detecting the position of the magnet rotor 5 (typically shown, direct detection by a magnetic sensor, phase of the stator winding 4) 7 can control the relay 43 and the switching element 2 based on signals from the position detection circuit 11, the current sensor 6, the voltage detector 10, the air conditioner controller 21, and the like. It is a control circuit.

  Although not shown in the figure, a control power supply DC converter for stepping down the voltage of the battery 1 for supplying power to the control circuit 7 and the gate drive circuit of the switching element 2 is separately provided.

  FIG. 10 is a layout diagram of a conventional vehicle air conditioner.

  In FIG. 10, the air conditioner controller 21, the indoor blower fan 26, etc. are arranged in the vehicle interior, and the electric compressor 19, the outdoor heat exchanger 16, etc. are arranged outside the vehicle compartment. In most cases, the vehicle is parked outdoors. In other words, the vehicle air conditioner is also exposed to the outdoor temperature, and at low temperatures in winter, the refrigerant is likely to be liquid-backed mainly to the electric compressor 19 at the time of start-up, and an abnormal load is likely to be applied. . Further, in order to obtain heating comfort in a short time immediately after boarding, rapid heating start-up is required. Under such circumstances, since the sound from the vehicle is conspicuous when the vehicle is stopped, silence is required.

  In other words, when heating operation of such an air conditioner is started at a low temperature, since the refrigerant is dissolved in the lubricating oil in the compressor, the refrigerant circulation amount does not increase easily even if the compressor is driven, The heating rise time may become long, or the lubricating action may be hindered and adversely affect the compression mechanism.

  Therefore, in addition to directly heating the compressor with a heating device such as a heater, a method of heating the compressor before starting normal operation of the electric compressor (hereinafter referred to as preheating operation) has been performed (for example, Patent Documents). 1).

As a method for this, there is a technology that heats a compressor by generating heat without rotating the motor by supplying an AC voltage with a frequency higher than that during normal operation to the motor that drives the compressor. It is disclosed.
Japanese Patent Publication No.4-2859

However, in the above-described conventional configuration, the heat generated by the motor is due to the power consumption of a small resistance component existing in the stator winding, so that a large current needs to flow in order to generate sufficient heat. Since a large inductance component exists in the stator winding, it is necessary to energize the stator winding for a long time in order to flow a large current (if the current is i, the applied voltage is V, and the inductance is L). V = Ld · i / dt, so V∫dt = L∫di, and the longer the voltage application time, the larger the current).

  However, when energizing for a long time, the frequency of the AC voltage supplied to the motor cannot be increased. Therefore, when an AC voltage having a high frequency is supplied to the electric motor, sufficient current does not flow and sufficient heating cannot be performed. On the other hand, when an AC voltage having a low frequency is supplied to the motor, a sufficient current flows and sufficient heating can be performed, but the frequency becomes audible and noise (electromagnetic sound) is generated.

  In electric vehicles, hybrid vehicles, and fuel cell vehicles, the driving energy source is electricity (batteries), so the power used for air conditioning functions such as preheating operation is small to save vehicle performance (power saving). There is a need to.

  In other words, in the conventional method of generating heat by an electric motor, the inverter device also generates heat due to the power loss of the inverter operation of the inverter device in order to supply the AC voltage to the electric motor. Not used. Therefore, since the power consumption of the DC power source is both the heat generation of the motor and the heat generation of the inverter device, excessive power is required for the purpose of heating the compressor.

  The present invention solves such a conventional problem, and an object of the present invention is to provide an air conditioner that can perform a sufficient preheating operation with low noise and power saving.

  Moreover, the preheating method of the compressor heated without requiring heating apparatuses, such as a heater, is provided.

  In order to solve the above-described problem, the air conditioner of the present invention energizes the stepped-down DC voltage from the DC converter using a switching element of the inverter device so that a DC current flows to the winding of the motor. The compressor is heated by the heat generated in the winding by the direct current.

  Thereby, since it is a direct current, no noise due to electromagnetic noise is generated in the preheating operation. Therefore, regardless of the relationship between noise and heating, the output of the DC converter can be adjusted as necessary, and sufficient heating can be performed. Further, it is possible to save power by adjusting the output of the DC converter to an optimum heating state.

  Moreover, it can be heated substantially uniformly by switching and heating the windings of each phase.

  Also, in order to utilize the heat generated by the inverter device and DC converter during preheating, these are arranged on the bottom surface of the compressor, or arranged on a portion that is difficult to be heated by the windings, so that the compressor can be more effectively used. It is for heating.

  The air-conditioning apparatus of the present invention can perform sufficient heating in the preheating operation of the electric compressor without generating any noise and without using wasted power.

  Therefore, an air conditioner capable of sufficient preheating operation with low noise and power saving can be obtained.

  According to a first aspect of the present invention, a DC voltage that has been stepped down from a DC converter is energized using a switching element of an inverter device so that a direct current flows to a winding of an electric motor, and a compressor is generated by heat generation of the winding by the direct current. Heat.

  Thereby, since it is a direct current, no noise is generated in the preheating operation. Therefore, regardless of the relationship between noise and heating, the output of the DC converter can be adjusted as necessary, and sufficient heating can be performed. Further, the output of the DC converter can be adjusted to an optimum heating state, and power saving can be achieved. When a conventional high-frequency AC voltage is applied, a leakage current is generated from the compressor, but none is generated.

  According to a second invention, in the first invention, the windings to be energized for preheating are sequentially changed, thereby eliminating the unevenness of the heat generation part and performing uniform and effective heating.

  According to a third invention, in the first and second inventions, the output of the DC converter is adjusted on the basis of the temperature of the compressor, thereby enabling accurate heating to the minimum necessary and saving power. Can be achieved.

  According to a fourth aspect, in the first to third aspects, the DC converter is used as a DC voltage source to be DC / AC converted during the DC / AC conversion operation of the inverter device. At the time of DC / AC conversion for driving the electric motor, voltage is boosted and the electric motor is driven with high efficiency and high output by PAM modulation. That is, it can be realized only by adding a step-down function (step-down switching element, diode) to the step-up DC converter for driving the electric motor with high efficiency and high output.

  In a fifth aspect based on the first to third aspects, the DC converter is used as a power source for controlling the inverter device. Since the control power supply of the inverter device is a low voltage of several tens to several volts, it is suitable as a preheating operation voltage. During the preheating operation, since the electric motor is not driven, the power consumption of the control power supply can be reduced. Therefore, it can be realized without adding a special circuit.

  According to a sixth invention, in the first to fifth inventions, the inverter device is integrally disposed and mounted on the compressor. Thereby, the heat generated by the inverter device during the preheating operation can also be used for heating the compressor, and power saving can be achieved.

  According to a seventh aspect, in the sixth aspect, the inverter device is disposed below the compressor. Therefore, the compressor can be effectively heated from the lower side of the compressor by the heat generated by the inverter device, and further power saving can be achieved. Further, when the electric motor is driven, the inverter device can be reduced from being heated by the heat of the compressor.

  According to an eighth invention, in the sixth or seventh invention, when the electric motor is installed in the high pressure shell of the compressor, the inverter device is arranged on the low pressure side of the compressor. Thus, during the preheating operation, the high pressure side of the compressor is heated by the electric motor, and the low pressure side of the compressor is heated by the inverter device. Therefore, the compressor can be heated uniformly, and it is possible to effectively prevent the refrigerant from entering the lubricating oil, the liquid back, etc. from both the high pressure side and the low pressure side. Further, when the electric motor is driven, the inverter device is cooled by the low-temperature and low-pressure side, so there is no need to add a special cooling mechanism.

  According to a ninth invention, in the sixth or seventh invention, when the electric motor is installed in the low pressure shell of the compressor, the inverter device is arranged on the high voltage side. Thus, during the preheating operation, the low pressure side of the compressor is heated by the electric motor, and the high pressure side of the compressor is heated by the inverter device. Therefore, the compressor can be uniformly and effectively heated.

  A tenth aspect of the invention is that in the sixth to ninth aspects of the invention, the DC converter is accommodated in the inverter device. As a result, the heat of the DC converter can also be used for heating the compressor, and further power saving can be achieved.

An eleventh aspect of the invention is that in the first to tenth aspects of the invention, the air conditioner is a vehicle air conditioner. Therefore, it is easy to liquid back, rapid cooling and heating rise is required, and low noise is required. Therefore, the present invention is effective.

  In a twelfth aspect of the invention, a method is used in which a DC voltage of a DC power supply is energized using a switching element of an inverter device so that a DC current flows to a winding of an electric motor, and the compressor is heated by heat generation of the winding due to the DC current. It is.

  Accordingly, the compressor can be preheated without a heating device such as a heater, and the reliability of the compressor can be improved. Further, since it is a direct current, no noise is generated in the preheating operation, and no leakage current from the compressor as in the case of applying a conventional high frequency alternating voltage is generated.

  A thirteenth aspect of the invention is the method of sequentially changing the windings to be energized for preheating in the twelfth aspect of the invention, thereby eliminating the bias of the heat generating portion and making it possible to uniformly and effectively preheat the compressor.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 shows an electric circuit diagram for driving the electric compressor according to Embodiment 1 of the present invention. Compared to the conventional electric circuit diagram (FIG. 9), a DC converter 51 is provided between the battery 1 and the inverter device 46, and the motor temperature for detecting the temperature of the motor 31 (electric compressor 19) is provided. A temperature sensor 8 for detection is installed. On the other hand, the inverter device 46 is not provided with the relay 43 and the charging resistor 49. Note that the control power supply DC converter for stepping down the voltage of the battery 1 for supplying power to the control circuit 7 and the gate drive circuit of the switching element 2 is also provided separately.

  Further, the configuration of the vehicle air conditioner, the electric compressor, and the vehicle arrangement are the same as those shown in FIGS. 7, 8, and 10 except for the above-described changes.

  Regarding the above configuration, first, the driving of the electric motor in normal cooling or heating operation will be described.

  In starting the inverter device 46, first, the switching element 50 of the DC converter 51 is turned ON. As a result, a charging current flows from the battery 1 to the capacitor 41 via the coil 52 and the diode 54, and the capacitor 41 is charged to the voltage of the battery 1. At this time, since the charging current is suppressed by the inductance of the coil 52, the conventional charging resistor 49 for preventing inrush current is unnecessary.

  When the charging of the capacitor 41 is completed (the control circuit 7 determines based on the output of the voltage detector 10 or the like), the control circuit 7 drives the switching element 2 of the inverter circuit unit 40 and starts DC / AC conversion by PWM. . At this time, since the current flows through the switching element 50, the coil 52, and the diode 54, the conventional relay 43 is unnecessary. Then, the electric motor 31 is driven based on the rotational speed command signal from the air conditioner controller 21. If necessary, the control circuit 7 causes the DC converter 51 to perform a step-up operation, causes the switching element 2 of the inverter circuit unit 40 to perform a PAM operation, and drives the motor 31 with high efficiency and high output. The step-up operation is performed by switching of the step-up switching element 53 and rectification by the diode 54.

  Next, the preheating operation when the outside air temperature is low will be described.

  The temperature of the electric compressor 19 (the electric motor 31) is detected by the electric motor temperature detecting temperature sensor 8, and the control circuit 7 starts the preheating operation when the detected temperature is lower than a predetermined value (for example, 0 ° C.).

  First, the step-down switching element 50 is operated, and the DC output voltage of the DC converter 51 is made lower than the voltage of the battery 1. This voltage is detected by the voltage detector 10. When the detected voltage reaches a predetermined value, the control circuit 7 turns on U, Y, and Z of the switching element 2. As a result, a direct current flows through the stator winding 4.

As an example, the DC output voltage of the DC converter 51 is 10 V, the ON voltage of the switching element 2 is 2 V, and the resistance value of each phase of the stator winding 4 is 1Ω. The DC current value of the U-phase winding is (10V-2V-2V) / (1Ω + 0.5Ω) = 4A, and the DC current value of each of the V-phase and W-phase windings is 4A / 2 = 2A. Therefore, the power consumption (heat generation amount) of the U-phase winding is 1Ω × (4A) ² = 16W, and the power consumption (heat generation amount) of each V-phase and W-phase winding is 1Ω × (2A) ² = 4W. . Accordingly, the power consumption (heat generation amount) of the entire stator winding 4 is 24 W.

  In the above configuration, since the current flowing to the stator winding 4 is a direct current, no noise is generated. Furthermore, no leakage current from the compressor occurs. Therefore, sufficient heating can be performed regardless of noise and leakage current. This function can be realized only by adding a step-down function (step-down switching element 50, diode 58) to the step-up DC converter.

  Since the power consumption (heat generation amount) in this winding can be adjusted by the DC output voltage of the DC converter 51, the temperature detected by the motor temperature detection temperature sensor 8 is the temperature or liquid at which the refrigerant does not dissolve in the lubricating oil. It may be adjusted to reach a temperature that can prevent back.

  As a result, it is possible to accurately control the minimum necessary heating, and power saving can be achieved.

  However, when a direct current is passed through the stator winding 4 in this way, as described above, the power consumption (heat generation amount) differs depending on the phase, resulting in an imbalance. Therefore, it is preferable to sequentially change the switching elements 2 to be turned on. As an example, the energization pattern 1 is U, Y, Z is ON, the energization pattern 2 is V, X, Z is ON, and the energization pattern 3 is W, X, Y is ON. Then, the energization patterns 1 to 3 may be sequentially selected.

  As a result, the unevenness of the heat generating portion is eliminated, and substantially uniform and effective heating can be performed.

  If the switching elements 2 to be turned ON are U and Y, the same current flows through the U-phase winding and the V-phase winding of the stator winding 4 to generate the same power consumption (heat generation amount), and the W-phase. The winding does not generate heat. In this method, the switching elements 2 to be turned on may be V and Z, and the switching elements 2 to be turned on may be W and X, and the energization pattern in which the windings of the respective phases generate heat may be sequentially selected. In other words, the method is not particularly limited as long as it is a method capable of eliminating unevenness of the heat generation part by sequentially selecting energization patterns and performing almost uniform heating.

  As described above, in the present embodiment, an air conditioner that enables sufficient preheating operation with low noise and power saving can be obtained.

(Embodiment 2)
FIG. 2 shows an electric circuit diagram for driving the electric compressor according to the second embodiment of the present invention.

  The DC converter 55 provided between the battery 1 and the inverter device 47 converts the voltage of the battery 1, which is not illustrated in the background art and the first embodiment, and supplies power to the control circuit 7, the switching element 2, and the like. It is a DC converter for control power supply for supplying.

  A diode 59 is newly provided between the inverter device 47 and the DC converter 55. Further, the temperature sensor 8 for detecting the motor temperature for detecting the temperature of the electric motor 31 (electric compressor 19) is installed as in the first embodiment.

  The configuration of the vehicle air conditioner, the electric compressor, and the vehicle arrangement are the same as those shown in FIGS. 7, 8, and 10 except for the above changes.

  The normal operation of the above configuration will be described.

  In starting the inverter device 47, the capacitor 41 is first charged to the voltage of the battery 1 by the charging resistor 49. The control circuit 7 is supplied with power by stepping down the voltage of the battery 1 from the DC converter 55.

  When the charging of the capacitor 41 is completed (the control circuit 7 determines based on the output of the voltage detector 10 or the like), the control circuit 7 closes the relay 43, drives the switching element 2 of the inverter circuit unit 40, and performs direct current by PWM. / Start AC conversion. Then, the electric motor 31 is driven based on the rotational speed command signal from the air conditioner controller 21.

  Next, the preheating operation will be described.

  When the heating operation is stopped (the electric motor 31 is stopped) at a time when the outside air temperature is low, the temperature of the entire air conditioner gradually decreases. At this time, the inverter circuit unit 40 is in a stopped state. Further, the relay 43 is opened. On the other hand, the DC converter 55 is functioning.

  The capacitor 41 is charged to a low voltage via the diode 59 and supplied to the control circuit 7 as well. Therefore, the temperature drop of the electric compressor 19 (electric motor 31) is detected by the temperature sensor 8 for electric motor temperature detection.

  When the detected temperature is lower than a predetermined value (for example, 0 ° C.), the control circuit 7 starts the preheating operation. Since a low voltage has already been supplied to the inverter circuit unit 40 from the DC converter 55, U, Y, and Z of the switching element 2 are turned ON. As a result, a direct current flows through the stator winding 4. Assuming that the low voltage to the inverter circuit unit 10 is 10V, the ON voltage of the switching element 2 is 2V, and the resistance value of each phase of the stator winding 4 is 1Ω, calculation example of power consumption (heat generation amount) in the first embodiment Will be the same.

  In the above configuration, the DC converter 55 as the control power source outputs a low voltage of several tens of volts to several volts, and is therefore suitable as a voltage for preheating operation. Therefore, the preheating operation function can be realized without adding a special circuit.

  The power consumption (heat generation amount) in this winding can be adjusted by the DC output voltage of the DC converter 55. At this time, it is desirable that the power supply voltage for the control circuit is stabilized by a regulator or the like.

  Furthermore, a normal DC converter for driving the electric motor 31 can be combined with the present embodiment.

(Embodiment 3)
FIG. 3 shows a partial cross-sectional view of an inverter apparatus-integrated electric compressor according to Embodiment 3 of the present invention. The electric circuit for driving the electric compressor is the same as that of the first embodiment.

  In FIG. 3, an inverter device 46 including a case 30 is installed under the electric compressor 42, and a terminal 39 is installed below for electrical connection with the inverter device 46. The inverter device 46 is connected to the DC converter 51, the air conditioner controller 21, and the like through a connection line 36. The connection line 36 is fixed to the case 30 with a harness clamp 35.

  The configuration of the vehicle air conditioner, the electric compressor, and the vehicle arrangement are the same as those shown in FIGS. 7, 8, and 10 except for the above changes.

  In the above configuration, when the electric motor 31 is driven by the inverter device 46, the inverter device 46 is disposed under the electric compressor 42, so that heat from the electric compressor 42 can be reduced.

  Further, during the preheating operation, the electric motor 31 (electric compressor 42) can be heated by the method according to the first or second embodiment. In addition, since the inverter device 46 is disposed on the bottom surface of the electric compressor 42, the heat generated by the inverter circuit unit 40 can be effectively utilized from below and heated.

  Further, in the present embodiment, the inverter circuit unit 40 is arranged at a place far from the electric motor 31 (near the compression mechanism unit 28). With this configuration, the electric compressor 42 can be widely heated by both the inverter circuit unit 40 and the electric motor 31. In addition, if the inverter circuit unit 40 is disposed below the electric motor 31, both the inverter circuit unit 40 and the electric motor 31 can be intensively and strongly heated.

  Here, the power consumption (heat generation amount) of the inverter circuit unit 40 is calculated by applying the calculation example of the first or second embodiment. The power consumption (heat generation amount) of U of the switching element 2 is 2V × 4A = 8W, and the power consumption (heat generation amount) of Y and Z is 2V × 2A = 4W. Therefore, the power consumption (heat generation amount) of the entire switching element 2 is 16W.

  That is, the heating power for preheating operation according to the present embodiment is 40 W together with 24 W of the electric motor 31. Next, a method for more effectively using the heat generated by the inverter device 46 will be described.

  FIG. 4A shows a perspective view of the inside of the inverter device 46. The inverter circuit unit 40 is connected under the circuit board 29 constituting the control circuit 7 and the like, and the inverter circuit unit 40 is closely fixed to the heat transfer unit 45, and the heat of the inverter circuit unit 40 is transferred to the heat transfer unit 45. It is. Then, the electric compressor 42 is heated by the heat transfer device 45. At this time, it is more effective to use the heat generated by the switching elements 50 and 53 and the diode 54 constituting the DC converter 51 through the heat transfer device 45.

  FIG. 4B shows a perspective view of the elements of the DC converter 51. The shape of the element is an example, but the connection lead is bent for connection to the circuit board 29.

Further, instead of the inverter device 46 shown in FIG. 1, an inverter device 47 shown in FIG. 2 may be used. Incidentally, the power consumption (heat generation amount) of the diode 59 in this case is also calculated as the heating power for preheating operation. When the ON voltage is 2 V, 2 V × 4 A = 8 W is added, and the heating power for preheating operation is 48 W.

  As shown in the present embodiment, the heat generated by all elements of the inverter device during the preheating operation can be used for heating the compressor. In addition, it is effective to heat the compressor with heat generated by the inverter device from the lower side of the compressor. As a result, further power saving can be achieved.

(Embodiment 4)
FIG. 5 shows a partial cross-sectional view of the inverter apparatus-integrated electric compressor according to the fourth embodiment of the present invention.

  In FIG. 5, an inverter device 46 including a case 37 is installed on the right side (low pressure side) of the electric compressor 44, and a terminal 39 is installed on the right side for electrical connection with the inverter device 46. Yes. The metal casing 60 of the electric compressor 44 has a shape in which the low pressure side of the metal casing 32 of the electric compressor 19 is changed. The inverter device 46 is connected to the DC converter 51, the air conditioner controller 21, and the like through a connection line 36. The connection line 36 is fixed to the case 37 with a harness clamp 35.

  The configuration of the vehicle air conditioner, the vehicle arrangement, and the electric compressor are the same as those shown in FIGS. 7, 8, and 10 except for the above changes.

  In this configuration, when the electric motor 31 is driven by the inverter device 46, the main heat generating unit inverter circuit unit 40 of the inverter device 46 is cooled by the low-pressure pipe 38. Therefore, no special cooling mechanism is required. Since the inverter circuit unit 40 is disposed below the low-pressure pipe 38, it is efficiently cooled. The electric motor 31 installed in the high pressure shell is cooled by the high pressure refrigerant.

  During the preheating operation, the electric motor 31 (the left side of the electric compressor 44) is heated by the method according to the first or second embodiment. On the other hand, the right side of the electric compressor 44 is effectively heated from below by the main heating unit inverter circuit unit 40 of the inverter device 46.

  The calculation of the power consumption (heat generation amount) of the inverter circuit unit 40 and the heat transfer structure are the same as in the third embodiment.

  An inverter device 47 may be used instead of the inverter device 46.

  Therefore, in the present embodiment, the compressor can be heated uniformly, and it is possible to effectively prevent the refrigerant from entering the lubricating oil, liquid back, etc. from both the high pressure side and the low pressure side. Further, when the electric motor is driven, the inverter device is cooled by the low-temperature and low-pressure side, so there is no need to add a special cooling mechanism.

  In the case where the electric motor 31 is installed in the low pressure shell of the compressor, if the inverter device 46 is mounted on the high pressure side, similar effects can be obtained during the preheating operation.

(Embodiment 5)
FIG. 6 shows an electric circuit diagram for driving the electric compressor according to the fifth embodiment of the present invention.

Compared to the first embodiment, the DC converter 51 is accommodated in an inverter device, and the inverter device is an inverter device 48. Moreover, the temperature sensor 9 for inverter temperature detection
Is installed.

  The operation and action when the electric motor 31 is driven by the inverter device 48 are the same as those in the first embodiment.

  Further, during the preheating operation, the electric motor 31 (electric compressor 42) is heated by the method according to the first or second embodiment. Further, it is heated by the heat generated by the DC converter 51 in addition to the inverter circuit section 40.

  The power consumption (heat generation amount) of the DC converter 51 having the above configuration is calculated under the same conditions as in the example of the first embodiment. If the ON voltage of the step-down switching element 50, the diode 54, and the diode 58 is 2V, the DC current value is 4A, so that approximately 4A × 2V (switching element 50 and diode 58) + 4A × 2V (diode 54) = 16W. Become. That is, the heating power for preheating operation according to the present embodiment is 56 W including 24 W of the motor 31 and 16 W of the inverter circuit unit 40.

  FIG. 4A shows an internal perspective view of the inverter device 48. The inverter circuit unit 40 is connected under the circuit board 29 constituting the control circuit 7 and the like, and the heat of the inverter circuit unit 40 is transferred to the heat transfer unit 45. Then, the electric compressor 42 is heated by the heat transfer device 45. Further, as shown in FIG. 4B, the step-down switching element 50, the diode 54, and the diode 58 are also electrically connected to the circuit board 29 in a shape in which the connection leads are bent, and are attached to the heat transfer unit 45 to transfer heat.

  At this time, if the temperature of the heat transfer device 45 is detected by the temperature sensor 9 for detecting the inverter temperature, the output of the DC converter 51 is varied, and the heating power for preheating operation is adjusted, the power consumption can be further suppressed. .

  Similarly, in FIG. 2 in the second embodiment, DC converter 55 may be accommodated in the inverter device. In this case, the switching element 57 is attached to the heat transfer unit 45. When the power consumption (heat generation amount) of the switching element 57 is about 4 W, the heating power for preheating operation is 52 W, including 24 W of the electric motor 31, 16 W of the inverter circuit unit 40, and 8 W of the diode 59.

  In the present embodiment, the heat of the DC converter can also be used for heating the compressor. Therefore, further power saving can be achieved.

  Since the vehicle air conditioner is easy to liquid back and requires rapid cooling and heating, and low noise is required, it is effective to preheat the electric compressor by applying the embodiments described above. It is.

  As described above, since the air conditioner according to the present invention enables sufficient preheating operation with low noise and power saving, it can be applied to air conditioners in homes, offices, factories, and the like. Moreover, it is applicable also to uses, such as an apparatus which heats using a refrigerating cycle.

Electric circuit diagram for driving the electric compressor according to Embodiment 1 of the present invention Electric circuit diagram for driving the electric compressor in the second embodiment of the present invention Partial sectional view of an inverter-integrated electric compressor according to Embodiment 3 of the present invention. (A) The perspective view inside the inverter apparatus in Embodiment 3 and 5 of this invention, (b) The perspective view of the element of the inverter apparatus Partial sectional view of an inverter-integrated electric compressor according to Embodiment 4 of the present invention. Electric circuit diagram for driving the electric compressor in the fifth embodiment of the present invention Configuration diagram of a vehicle air conditioner equipped with a conventional electric compressor Partial sectional view of a conventional electric compressor Electric circuit diagram for driving a conventional electric compressor Vehicle layout of conventional air conditioner

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Battery 4 Stator winding 8 Temperature sensor for electric motor temperature detection 19 Electric compressor 31 Electric motor 42 Electric compressor (an inverter apparatus is arrange | positioned down)
44 Electric compressor (inverter device is arranged horizontally)
46 Inverter device (DC converter connection for buck-boost)
47 Inverter unit (DC converter connection for control power supply)
48 Inverter device (built-in DC converter for buck-boost)
51 DC converter (for buck-boost)
55 DC converter (for control power supply)

Claims (10)

DC power source, DC converter for DC / DC conversion of DC voltage of DC power source, inverter device for DC / AC conversion of DC voltage and output of AC current to drive motor, and compression driven by motor In addition to the function of driving the electric motor, the inverter device is energized so that a direct current flows to the winding of the electric motor by using a switching element to reduce the direct-current voltage from the DC converter. And an air conditioning apparatus having a preheating operation function of heating the compressor by heat generation of the winding by energization of the direct current. The air conditioner according to claim 1, wherein windings to be energized are sequentially changed for preheating. The air conditioner according to claim 1 or 2, wherein the output of the DC converter during the preheating operation is adjusted based on the temperature of the compressor. The air conditioner according to any one of claims 1 to 3, wherein the DC converter is used as a DC voltage source that is DC / AC converted when the inverter device performs a DC / AC conversion operation to drive the motor. The air conditioner according to any one of claims 1 to 3, wherein the DC converter is also used as a power source for controlling the inverter device. The air conditioner according to any one of claims 1 to 5, wherein the inverter device is disposed integrally with the compressor. The air conditioner according to claim 6, wherein the inverter device is disposed below the compressor. The air conditioner according to claim 6 or 7, wherein the electric motor is installed in a high pressure shell of the compressor , and the inverter device is disposed on a low pressure pipe side. The air conditioner according to any one of claims 6 to 8 , wherein the DC converter is accommodated in an inverter device. Air conditioning apparatus according to claim 1 to 9, characterized in that the air conditioning apparatus and a vehicle.

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